This invention relates generally to means for maintaining the strafing pit areas of Air Force gunnery ranges in proper condition to minimize the risk of projectile ricochet damage to aircraft utilizing the ranges for gunnery practice.
The U.S. Air Force maintains a number of gunnery ranges for use in the practice firing of relatively small caliber armament on jet aircraft. All such ranges include strafing pits, a strafing pit being an area where an unfurled drag chute target is suspended on poles above the ground for low flying planes to shoot at as they overfly it. Such strafing pits are used primarily for firing practice with 20 and 30 mm guns. If the ground area of a strafing pit is hardpacked or contains rocks and spent shells from previous target runs, some of the fired projectiles from a plane coming in at a low angle to shoot at the target can ricochet upwardly into the path of the fast moving plane and thereby pose a danger to the aircraft and its pilot. Such ricochets can even cause plane crashes and pilot deaths. Consequently, efforts have been made by the Air Force to maintain the ground surface areas of strafing pits in condition to minimize the possibility of such ricocheting and risk of injury or death to pilots and destruction of highly sophisticated and costly jet aircraft. Such efforts, however, have not met with great success.
Past efforts to increase the safety of strafing pit areas have involved disking operations to loosen and soften the earth in such areas, but such disking was found to be extremely time consuming, taking, for example, from 11/2 to 2 days to cover the ground from 150 feet in front of the target to 200 feet behind it (the area to be maintained under Air Force requirements.) Heretofore any rocks turned up by the disking operation were removed by hand, an extremely slow and inefficient way of going about it. The removal of spent projectiles from strafing pits with an electromagnet has been considered in the past, but never successfully carried out. For one thing, no satisfactory method of transporting the magnet, which was quite heavy, across the soft, disked earth, characterized by areas of varying density, was ever found. Moreover, I have determined that the type of electromagnet heretofore contemplated for use in the magnetic sweeping of strafing pits was underpowered and probably incapable of removing spent projectiles from strafing pit areas even if a way had been found to move it over such areas while maintaining it at optimum height above ground level for the purpose.
For the above reasons, previous attempts to maintain strafing pit areas in Air Force gunnery ranges in proper condition to minimize ricochets during target runs for purposes of safety have been not only costly, but inefficient and only partly effective.